Acute and chronic toxicity of nano-scale TiO₂ particles to freshwater fish, cladocerans, and green algae, and effects of organic and inorganic substrate on TiO₂ toxicity

Abstract

This research evaluated the toxicity of TiO₂ nanoparticles to freshwater aquatic organisms and the effects of organic and inorganic material on TiO₂ toxicity. The fathead minnow was much less acutely sensitive to TiO₂ (LC50 500 mg/l and higher) than Ceriodaphnia dubia and Daphnia pulex (mean LC50 values 7.6 and 9.2 mg/l, respectively). Total organic carbon levels of 1.5 mg/l decreased TiO₂ acute toxicity to C. dubia (LC50 > 100 mg/l), but kaolinite clay decreased TiO₂ toxicity to a lesser extent. In chronic toxicity tests, the green algae Pseudokirchneriella subcapitata was more sensitive to TiO₂ (IC25 1–2 mg/l) than C. dubia (IC25 9.4–26.4 mg/l) and the fathead minnow (IC25 values over 340 mg/l). Study results indicate that the specific organisms exposed and the effects of water quality parameters on TiO₂ toxicity should be considered in hazard evaluations of this nanoparticle.

• TiO₂
• nanoparticles
• aquatic toxicity
• bioavailability